Ok I’m setting up Will’s 400 watt mobile system with alternator charging.
https://www.mobile-solarpower.com/simplified-400-watt-fewer-wires-and-alternator-charging.html
I’m using 8 Fortune 100Ah LiFePo4 batteries in a 4P4S configuration. Here is Will’s Youtube video on this setup...
here are the specs for the batteries...
View attachment 9683
I want to set the parameters in the BMS to conservative settings in order to make my batts last as long as possible. But I’m confused as to nomenclatur. For instance Will, in another posting, list’s absorption, float and invertercutoff as value‘s he would use, but this BMS has no such setting.
https://diysolarforum.com/threads/r...e-for-diy-lifepo4-batteries-sticky-post.5101/
Also can anyone explain what a tripper value and a release value does? As far as I can tell there is no manual for this, on github or reddit.
Here are the factor settings, can someone help me out here?
View attachment 9685
OK, so float and absorbtion voltage are settings on your charger. The BMS will disconnect the charger when the voltage rises to the Trigger value, either on one cell or the whole pack. The release value is when charging will be re-enabled.
example: using an unregulated charger, cell 1 rises to 3.650v (the high voltage cutoff, at this point the cell is over 100% charged) the BMS will disconnect/ block any more charging current. It will stay like this until the cell drops down to 3.500v, (from discharging)
You should be using a regulated charger that has a voltage limit (absorption voltage limit) set at like 14.2 to 14.4
With the lithium pack that I've been experimenting with, it tends to cut off for a single cell high voltage before the whole pack gets to 14.4v, but I am using the cheapest cells I could find. (possibly mismatched capacities)I have some good cells on the way.
Inverter cutoff is a setting on your inverter which is probably not adjustable, none of my inverters have that adjustment. The low voltage cutoff (pack or single cell) will cutoff the discharge current at whatever value you set it. Recommend 2.5v per cell / 10v pack.
Below 3.000v per cell there is like 1% of the capacity left so if you want to preserve cell life set the low voltage at 2.9v per cell / 11.6v pack
likewise, they are almost fully charged at 3.4v per cell.
A warning tho- having the BMS cutoff current can cause voltage spikes up the line that might damage your charger or load. Thats why they should be regulated so as to not reach the BMS cutoffs if possible.
The Github and reddit pages are a work in progress, I will probably polish this post a bit and put it in both places.
If I missed part of your question please let me know.